1. Field of the Invention
The present invention relates to an apparatus for effecting the pressure or vacuum testing of selected zones of a subterranean bore, such as an uncased well bore.
2. History of the Prior Art
In recent years, there has been considerable interest developed in the utilization of subterranean well bores for the storage of nuclear waste materials. If such highly dangerous materials are to be deposited in a well bore, there must be reasonable assurance that the nuclear waste materials will not migrate from the deposited zone in the well bore due to the porosity of the formation in that zone. There should also be reasonable assurance that fluids in the selected formation will not seep out of the well bore and cause a dispersion of the nuclear waste material from the selected subterranean deposit zone.
A method and apparatus for conducting the testing of a selected zone of an uncased subterranean well bore is disclosed in co-pending application Ser. No.: 859,441 filed 5/5/86, and assigned to the Assignee of the instant invention. In the meantime, it has been realized that the hydrological testing should not be limited to subterranean well bores but could well be applied to horizontal or evenly upwardly directed passages which are initiated from a lower level of a mine shaft. It is therefore desirable that suitable apparatus be provided which may be employed in any form of subterranean bore, so long as the bore is reasonably cylindrical in configuration.
One of the problems encountered in designing such hydrological survey apparatus is the necessity for many fluid passages required to make an effective hydrological survey of a subterranean bore. A pair of axially spaced inflatable packers still constitutes the most efficient apparatus for effecting the isolation of a selected zone of the subterranean bore. To inflate such packers and then concurrently monitor the fluid pressures existing between the inflatable packers and in the zones immediately above and below the inflatable packers requires a plurality of separate fluid conduits which, as a practical matter, cannot be effectively mounted on the exterior of a tubing string employed to insert the inflatable packers into the subterranean bore. When an attempt is made to dispose the various fluid passages within the central bore of the tubing string, the apparatus becomes unnecessarily complex as illustrated by the apparatus disclosed in the above referred to co-pending application. Furthermore, the bore of the apparatus is completely filled with fluid passages and pressure transducers so that if it is desired to utilize the same apparatus for supplying a large quantity of treatment fluid to the isolated zone between the two packers, the entire hydrological testing apparatus has to be removed and a new fluid treatment apparatus inserted in its place. There is a need, therefore, for an improved hydrological testing apparatus which will efficiently provide the plurality of fluid passages required for the operation of the inflatable packers and the monitoring of the various zones determined by the inflation of the packers, and which may be readily converted to a fluid treatment apparatus.